贵刊2013年8月上第20页刊登了《从一道考题的释疑中体会的等价性》一文(下称文[1])。文[1]以2009年高考浙江文科卷第21题为例,从错解出发,剖析错误原因,寻找问题的充要条件,进而实现等价转换.但是在文[1]中的正解1中却出现了两次转换不等价,为叙述方便,现把文[1]中正解1部分摘抄如下: August 2013 on the 20th page published in your article “from a test of doubt to understand the equivalent of article” (hereinafter referred to as the text [1]). The article [1] takes the 21st case of the Zhejiang college entrance examination in 2009 as an example, starting from the misunderstanding, analyzing the error reason and finding the necessary and sufficient conditions of the problem, so as to realize the equivalent conversion. However, in the positive solution 1 in [1] It appears that the two conversions are not equivalent. For the convenience of narration, the part of the text [1] in positive solution 1 is extracted as follows: